In this study, the effect of the fin surface on the electrical performance of passively cooled photovoltaics (PV) modules equipped with flat (${\mathrm{PV}}_{\mathrm{f}}$ ) and tread (${\mathrm{PV}}_{\mathrm{t}}$ ) surface finned heat sinks was experimentally investigated. ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules were fabricated with heat sinks by filling phase change material (paraffin)/aluminum chip mixture between the PV module and heat sink. The mean ambient temperature, solar radiation, and solar power during the experiment were about 13°C, $864\mathrm{W}/{\mathrm{m}}^2$ , and 247, respectively. The electrical power of the ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules was increased by 10.84% and 17.2%, respectively, while the average temperature was decreased by 11.78% and 16.5%, respectively, compared to the PV module. The ${\mathrm{PV}}_{\mathrm{t}}$ module provided 5.37% more effective cooling and a 5.74% higher electrical power than the ${\mathrm{PV}}_{\mathrm{f}}$ module. The electrical efficiency of the PV module was 11.35%, and the rate of increase was 1.21% and 1.95% for the ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules via cooling. Compared to the PV module, the electrical exergy of the ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules increased by 10.84% and 17.2%, respectively, at an average solar exergy of 230.61 W, while their thermal exergy decreased by 23.64% and 32.3%, respectively. Compared to the ${\mathrm{PV}}_{\mathrm{f}}$ module, the thermal exergy of the ${\mathrm{PV}}_{\mathrm{t}}$ module was reduced by 11.34%, and the electrical exergy was increased by 5.74%. The increase in exergy efficiency is 3.14% and 4.51% for ${\mathrm{PV}}_{\mathrm{f}}$ and ${\mathrm{PV}}_{\mathrm{t}}$ modules versus the PV module. A small part of solar energy is converted into electricity, while a significant part is converted into heat and increases the temperature of the PV cells. An increase in the temperature of PV cells harms conversion efficiency and causes an increase in the share of converted heat and a decrease in electricity generation. The conversion efficiency can be improved by removing the accumulated heat of the module. In practice, there are various examples of passive and active cooling. Active cooling methods enhance heat transfer by forcing the fluid flow with a fan or pump to facilitate heat removal. Active cooling applications are heavy, expensive, and complicated. Natural heat convection can be maximized with heat spreaders or heat sinks during passive cooling. Passive cooling may not dissipate heat as effectively as active cooling. Passive cooling systems are cheap, lightweight, and uncomplicated, and they can become even more valuable as their thermal efficiency increases. This study addresses the effect of the heat sink fin surface on the cooling and electrical performance of flat and tread finned heat sinks coupled PV modules that are paraffin/aluminum chips blend backplane filled. 1st and 2nd law PV module efficiencies improved by about 1.21% and 1.95% and 3.14% and 4.51% with flat and tread finned heat sinks, respectively.

Long-term savings can be achieved by small household improvements to deal with the increasing energy costs that are important to all of us. Hot shower greywater is discharged to the environment with a significant amount of thermal energy. In this study, unlike the studies in the field, the recoverability potential of the shower greywater thermal energy was experimentally studied and compared by the horizontal and vertical connection of the helical coil and brazed plate heat exchangers to a unit shower cabin. The shower water heating energy consumption of thermosiphon can be reduced by approximately 16.13% and 24.69% by mounting the helical coil heat exchanger horizontally and vertically. The saving rates reach 20.62% and 27.34% for brazed plate heat exchanger, too. It could be assessed that annual energy saving can be a minimum of 247.1 kWh and a maximum of 418.7 kWh for an average family of four people. The economic size of the saving was determined between $25.2 to $42.7, annually. The installation cost of a heat exchanger for a shower cabin is $87 and it was determined that the payback period could be 2 years. The reduction of carbon dioxide emission by the possible saving of energy is an estimated minimum of 203.85 kg/year. The study aims to contribute to the creation of literature for academic studies and design processes, as well as awareness for practitioners and investors.

In this study, the energy view of an oven of a 70-oven coke battery in an iron and steel plant was evaluated based on operating parameters and recommendations for improving efficiency were made. A mass and energy balance per coking period (p) was created for a coke oven. It was found that during each coking period, 51.2% of the energy input was used as coking heat. It is predicted that approximately 6.91% of the input energy can be recovered from flue gas into the combustion air. By recovering the heat from the flue gas into the combustion air, the efficiency of the coke oven can be increased to 58.11%. The heat of the coke oven gas can be recovered and converted into usable form, which accounts for 6.53% of the total energy input. With the dry quenching process, it is possible to recover around 24% of the energy used from coke. Improved oven insulation, heat recovery from coke and flue gases, and the dry quenching process can recover energy worth more than 25.19 GJ/p. The energy efficiency of the furnace was predicted to rise to 82.11% with coke dry quenching and to more than 88.64% with coke gas heat recovery and insulation upgrades. The potential economic savings are $2578, equivalent to a reduction in CO₂ emissions of 2.45 tons per coking period. The financial equivalent of emissions reductions from carbon trading could be $233 per coking period. Through the processes of dry coke quenching, coke gas (CG), and flue gas heat recovery and thermal insulation improvements of the coke battery, the total amount of recoverable energy can exceed 617,294 GJ/year.